Since a plane display such as a liquid crystal display (LCD) monitor, an LCD TV, or a plasma TV has special features of lightness, thinness, shortness, and compactness, therefore the plane display has become a mainstream of the display product and gradually replaces the traditional cathode ray tube (CRT). In general, a vertical type plane display has a pivotal shaft device between the main body and the base of the display such as a rotational shaft disposed on each of the two sides of the display to provide users an optimal viewing angle. In this way, the main body of the display can be adjusted with an inclined angle forward or backward with respect to the base.
Considering the limited space available, some plane displays are hung to a fixed object such as a partition in an office, an exhibition wall, or a public open space by means of a standard connecting plate being connected to the rear side of the display. The rear side of the connecting plate is then connected to a rotational shaft device which is capable of swinging in a transversal direction or a longitudinal direction, and the connecting plate is fixed onto a wall by a bottom plate, so that the plane display can be adjusted with an inclined angle forward or backward with respect to the base or rotated sideway.
However, it still cannot meet the requirements for the multi-directional adjustment. Therefore, related manufacturers usually adopt a spherical nest device, which is frequently used in lamps for the multi-directional adjustment. Such spherical nest device is disposed at the front side of the pivotal shaft assembly, and a lateral side of the spherical nest device is disposed next to a rotational shaft device, such that the spherical nest device can adjust the frictional torque by a two-way threaded connection. However, if one of the lateral sides is not secured, the spherical nest device will be loosened or fallen off, resulting in undesirable effects.